The present invention relates generally to systems and methods for improving the ease of pushing and steering three-wheeled all-terrain push chairs and strollers which are suited and sized for both adults and children and ruggedized for use on roads, trails, sand, and snow.
In recent decades, jogging strollers for young children and push chairs for larger people, including adults who typically deal with a disability or physical challenge of some kind, have been constructed to be more rugged than was the case for earlier generations of such vehicles, so that passengers and those pushing the vehicles can enjoy off-road unpaved trails and the like without undue difficulty.
Such prior art devices often employ three wheels, rather than four. Prior art push chairs or jogging strollers having three wheels have two fixed-directional wheels in the rear, and a third wheel centered toward the front of the push chair frame. In such constructions, the front wheel is usually fixed. A three-wheeled stroller, even with an in-line fixed front wheel, is significantly easier to steer than a four-wheeled stroller having the same diameter wheel sets, and three-wheeled contact is more stable than four. Steering may be accomplished by pushing down on the handlebar and lifting and turning the front wheel toward the desired direction. This must be done very often, even to maintain fairly straight paths. For children, their weight is small enough so that this is not overly difficult, though the repeated need to reset the direction of the stroller is inconvenient. However, for disabled adults, the lifting and re-setting process can be onerous, particularly for smaller-framed users.
Other approaches, as shown, for example, in U.S. Pat. No. 5,863,061, herein expressly incorporated by reference, utilize a front wheel which is mounted to the frame of the device using a vertical shaft disposed to permit the wheel to swivel about the vertical axis of the shaft for the purpose of steering the vehicle. However, these freely swivelable wheels also create steerability issues on rugged or soft terrain, such as sand, wherein the front wheel often becomes bogged down in the sand or loose dirt, in part because it is easily pushed by the terrain and swiveled toward a direction the user does not wish to go. As a result, the front of the stroller must often be lifted to free the wheel and swivel it back to the desired travel direction.